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Proper expression of metabolizable energy in avian energetics

Condor

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Abstract

We review metabolizable energy (ME) concepts and present evidence suggesting that the form of ME used for analyses of avian energetics can affect interpretation of results. Apparent ME (AME) is the most widely used measure of food energy available to birds. True ME (TME) differs from AME in recognizing fecal and urinary energy of nonfood origin as metabolized energy. Only AME values obtained from test birds fed at maintenance levels should be used for energy analyses. A practical assay for TME has shown that TME estimates are less sensitive than AME to variation in food intake. The TME assay may be particularly useful in studies of natural foods that are difficult to obtain in quantities large enough to supply test birds with maintenance requirements. Energy budgets calculated from existence metabolism should be expressed as kJ of AME and converted to food requirements with estimates of metabolizability given in kJ AME/g. Energy budgets calculated from multiples of basal metabolic rate (a component of maintenance energy), however, should be expressed as kJ of either TME or net energy depending on ambient temperature. Energy units should be stated explicitly to improve comparability and in some cases accuracy of energy analyses.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Proper expression of metabolizable energy in avian energetics
Series title:
Condor
Volume
86
Year Published:
1984
Language:
English
Contributing office(s):
Northern Prairie Wildlife Research Center
Description:
p. 396-400
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Condor
First page:
396
Last page:
400
Number of Pages:
4